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I'm sure Binky will get me at least once, the Hdpe won't be exposed as the 11mm polycarbonate is going over the top, so the armour is 15mm hdpe with 3mm ali corners and the polycarbonate on top of that. The axe is okay, not the best but it's only on a 3.5:1 reduction but even at that it seems to give a fair whack and it self rights very easily from any orientation although if I go too fast on the stick whilst it's upside down the chain can come off so it's a fine art.
It's on odd feeling reading how someone intends to destroy your creation :p I imagine you will make a mess of the nice paint job I have in mind!
Aha sorry Chris, I honestly would never destroy anybody machine, I'll give it some whacks given the chance but I'd never completely trash it
Hatchet is basically all done now, there's just one small thing i overlooked and now have absolutely no idea how i'm going to get it done in time. Dave Weston was round the other day and reminded me about tethers and explained how to attach them but since then i've been busy and haven't had a chance, the problems atm are that 1) i have no steel rope/wire with which to make said tether and 2) my axe head is 6mm hardox 400 and i only have a hand drill. Does anybody have any tips? i'm pretty limited on drill bits as well as they're either blunt or broken, the only half decent one i have is a 5mm cobalt bit.
Well if you could get hold of some rope or something you could make like a noose which fits over the axe head or something. Then you don't have to drill hardox.
Hadn't thought of that, i take it that would be allowed and i wouldn't be breaking any rules?
It's a strange feeling when you find yourself pricing up parts for a complete rebuild of your robot before you've even used t but that seems to be what i'm doing. I've come to the conclusion that i'm not very happy with how Hatchet has turned out, the chassis is all warped, it's very rough and bodged, the weapon works 'okay' but i feel it could be much better. So in light of this i already have a complete parts list and design for next years Hatchet.
Let me know what you think..
20mm Hdpe or Nylon Chassis depending on how well the 15mm Hdpe stands up this year, if it does horribly then Nylon it is.
2 18v Gimson drive motors with the same custom wheels i'm currently using
TZ85 speed controllers for the drive, depending on cost it may well be the 30 amp Botbitz but even they must be a HUGE step up from electronize
6s Lipo battery, found a 3300mah 25 - 50c Turnigy nano tech that looks quite nice
Same 30 amp Electronize driving the axe unless it proves unsuitable.
Same axe but a bigger reduction going from 3.5:1 to 6:1 for much improved acceleration
I like how the new scoop looks on the machine so if it turns out to be a keeper i'll get one made from Hardox.
I would look at UMHW or HDPE over nylon - they have better impact resistance and are usually better priced as well. Do you know why the frame warped? Perhaps we can work out how to avoid that next time.
Initially it warped as a result of being left near a radiator ( my mistake, got distracted), i did manage to use the heat gun to get it straightish again but it left a slight warp which now seems permanent. So it was entirely human error that warped the chassis, i've got nothing against HDPE as a material but i definitely want to look into an alternative that's a bit more sturdy.
That's interesting - I have tried to heat bend UMHW and while it is supposed to soften at a low temperature, I could never get it to permanently bend much. HDPE is closely related to UMHW so I don't know how you accidentally succeeded where I tried & failed :). Nylon is also a thermoplastic, so it can potentially heat warp too. There is a special high temperature UMHW called Tivar HOT (its a brand name) that has all the useful polyethelene traits and is very heat resistant.